The timing of mother-to-child transmission of human immunodeficiency virus infection and the neurodevelopment of children in Tanzania.

OBJECTIVE: To determine the association between the timing of mother-to-child transmission of human immunodeficiency virus (HIV)-1 and neurodevelopment among children born to HIV-1 infected mothers in Tanzania. METHODS: Bayley Scales of Infant Development (2nd edition) were administered at 6, 12 and 18 months to a subset of children (N = 327). Linear regression models and Cox proportional hazard models were separately fitted for the mental development index (MDI) and the psychomotor development index (PDI). RESULTS: Children who tested HIV-1-positive at birth had significantly higher decreases per month in MDI and PDI than HIV-1-negative children; 1.1 [95% confidence interval (95% CI), 0.4, 1.8] for MDI and 1.4 (95% CI 0.0, 2.7] for PDI. Children who tested HIV-1-positive after birth had an additional 0.6 (95% CI 0.1, 1.1) point decrease in MDI per month and a 0.6 (95% CI 0.0, 1.1) higher decrease in PDI each month than HIV-1-negative children. Testing HIV-1-positive at birth was associated with a 14.9 (95% CI 5.0, 44.7) times higher rate of becoming developmentally delayed in mental function, while testing HIV-1-positive after birth was associated with a 3.2 (95% CI 1.6, 6.4) times higher rate than in uninfected children. CONCLUSIONS: HIV-1 infected infants performed worse on tests of neurodevelopment and were significantly more likely to be identified as developmentally delayed in the first 18 months of life than HIV-1-negative children. The effect of HIV-1 infection on neurodevelopment scores and the risk of developmental delay may be highest among those who are already HIV-1 infected at birth.